Page 425 of 3502

TROUBLE DIAGNOSIS
ATC-47
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AT C
FUNCTION CONFIRMATION PROCEDURE
1. SET IN SELF-DIAGNOSIS MODE
1. Turn ignition switch ON.
2. Set in self-diagnosis mode as follows. Within 10 seconds after starting engine (ignition switch is turned
ON.), press A/C switch for at least 5 seconds.
CAUTION:
Press A/C switch after indicating LED of intake switch.
If battery voltage drops below 12 V during diagnosis STEP-3, door motor speed becomes slower
and as a result, the system may generate an error even when operation is normal. To avoid this,
start engine before performing this diagnosis.
Former STEP-1 (LEDs and display screen are checked) does not exist in this self-diagnosis func-
tion.
>> GO TO 2.
2. STEP-2: SENSOR CIRCUITS ARE CHECKED FOR OPEN OR SHORT CIRCUIT
Does code No. 20 appear on the display?
YES >> GO TO 3.
NO >> GO TO 13.
3. CHECK TO ADVANCE SELF-DIAGNOSIS STEP-3
Press temperature control switch (UP, driver side).
Advance to self
-diagnosis STEP-3?
YES >> GO TO 4.
NO >> Replace A/C and AV switch. (Temperature control switch is malfunctioning.)
4. CHECK TO RETURN SELF-DIAGNOSIS STEP-2
Press temperature control switch (DOWN, driver side).
Return to self
-diagnosis STEP-2?
YES >> GO TO 5.
NO >> Malfunctioning A/C and AV switch or unified meter and A/C amp. Refer to AT C - 9 4 , "
Self-diagno-
sis" .
5. STEP-3: MODE DOOR AND INTAKE DOOR POSITIONS ARE CHECKED
Press temperature control switch (UP, driver side).
Does code No. 30 appear on the display?
YES >> GO TO 6.
NO >> GO TO 14.
RHA970DB
RHA869DD
Page 426 of 3502

ATC-48
TROUBLE DIAGNOSIS
6. STEP-4: OPERATION OF EACH DOOR MOTOR IS CHECKED
1. Press temperature control switch (UP, driver side).
2. Press (DEF) switch. Code No. of each door motor test is indi-
cated on the display.
>> GO TO 7.
7. CHECK ACTUATORS
Refer to the following chart and check discharge air flow, air temper-
ature, blower motor voltage and compressor operation.
Checks must be made visually, by listening the sound, or by touching air outlets with hand, etc. for improper
operation.
*1: FOOT position during automatic control. Refer to AT C - 5 3 , "
AUXILIARY MECHANISM: FOOT POSITION
SETTING TRIMMER" .
OK or NG
OK >> GO TO 8.
NG >>
Air outlet does not change.
Go to Mode Door Motor Circuit. Refer to AT C - 6 3 , "
Mode Door Motor Circuit" .
Intake door does not change.
Go to Intake Door Motor Circuit. Refer to AT C - 6 9 , "
Intake Door Motor Circuit" .
Discharge air temperature does not change.
Go to Air Mix Door Motor Circuit. Refer to AT C - 6 6 , "
Air Mix Door Motor Circuit" .
Blower motor operation is malfunctioning.
Go to Blower Motor Circuit. Refer to AT C - 7 2 , "
Blower Motor Circuit" .
Magnet clutch does not engage.
Go to Magnet Clutch Circuit. Refer to AT C - 7 8 , "
Magnet Clutch Circuit" .
RHA495A
SJIA1002E
Code No. 41 42 43 44 45 46
Mode door position VENT B/L 1 B/L 2
FOOT
*1D/F DEF
Intake door position REC REC 20%FRE FRE FRE FRE
Air mix door position FULL COLD FULL COLD FULL HOT FULL HOT FULL HOT FULL HOT
Blower motor voltage 5 V 12 V 8.5 V 8.5 V 8.5 V 12 V
Compressor ON ON OFF OFF ON ON
Page 427 of 3502

TROUBLE DIAGNOSIS
ATC-49
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AT C
8. STEP-5: TEMPERATURE OF EACH SENSOR IS CHECKED
1. Press temperature control switch (UP, driver side).
2. Code No. 51 appears on the display.
>> GO TO 9.
9. CHECK AMBIENT SENSOR
Press (DEF) switch one time. Temperature detected by ambient
sensor is indicated on the display.
NOTE:
If the temperature indicated on the display greatly differs from the
actual temperature, check sensor circuit first, and then check sensor.
OK or NG
OK >> GO TO 10.
NG >> Go to Ambient Sensor Circuit. Refer to AT C - 9 6 , "
Ambi-
ent Sensor Circuit" .
10. CHECK IN-VEHICLE SENSOR
Press (DEF) switch for the second time. Temperature detected
by in-vehicle sensor is indicated on the display.
NOTE:
If the temperature indicated on the display greatly differs from the
actual temperature, check sensor circuit first, and then check sensor.
OK or NG
OK >> GO TO 11.
NG >> Go to In-vehicle Sensor Circuit. Refer to AT C - 9 9 , "
In-
vehicle Sensor Circuit" .
11 . CHECK INTAKE SENSOR
Press (DEF) switch for the third time. Temperature detected by
intake sensor is indicated on the display.
NOTE:
If the temperature indicated on the display greatly differs from the
actual temperature, check sensor circuit first, and then check sensor.
OK or NG
OK >> GO TO 12.
NG >> Go to Intake Sensor Circuit. Refer to ATC-105, "
Intake
Sensor Circuit" .
RJIA3240E
RJIA3241E
RJIA3242E
Page 430 of 3502
ATC-52
TROUBLE DIAGNOSIS
AUXILIARY MECHANISM: TEMPERATURE SETTING TRIMMER
The trimmer compensates for differences in range of ±3°C between temperature setting (displayed digitally)
and temperature felt by customer.
Operating procedures for this trimmer are as follows:
1. Begin Self-diagnosis STEP-5 mode. Refer to AT C - 4 6 , "
Self-diagnosis Function" .
2. Press fan control switch (UP) to set system in auxiliary mode.
3. Display shows “61” in auxiliary mechanism. It takes approximately 3 seconds to enable setting operation.
4. Press temperature control switch (driver side) as desired. Temperature will change at a rate of 0.5°C each
time a switch is pressed.
CAUTION:
A decimal point is not indicated during a setup of temperature compensation.
When battery cable is disconnected or battery voltage below 10 V, trimmer operation is canceled. Temperature
set becomes that of initial condition, i.e. 0°C.
PJIA0014E
Page 432 of 3502

ATC-54
TROUBLE DIAGNOSIS
Operational CheckBJS000FY
The purpose of the operational check is to confirm that the system operates properly.
CHECKING MEMORY FUNCTION
1. Press temperature control switch (UP, driver side) until 32°C is displayed.
2. Press fan control switch (DOWN) at least 2 seconds.
3. Turn ignition switch OFF.
4. Turn ignition switch ON.
5. Press AUTO switch.
6. Confirm that the set temperature remains at previous temperature.
7. Press fan control switch (DOWN) at least 2 seconds.
If NG, go to trouble diagnosis procedure for AT C - 9 5 , "
Memory Function" .
If OK, continue the check.
CHECKING BLOWER
1. Press fan control switch (UP). Blower should operate on low speed. The fan symbol should have one
blade lit.
2. Press fan control switch (UP) again, and continue checking blower speed and fan symbol until all speeds
are checked.
3. Leave blower on max. speed.
If NG, go to trouble diagnosis procedure for AT C - 7 2 , "
Blower Motor Circuit" .
If OK, continue the check.
CHECKING DISCHARGE AIR
1. Press MODE switch and DEF switch.
2. Each position indicator should change shape.
3. Confirm that discharge air comes out according to the air distri-
bution table. Refer to AT C - 3 1 , "
Discharge Air Flow" .
If NG, go to trouble diagnosis procedure for AT C - 6 3 , "
Mode Door
Motor Circuit" .
If OK, continue the check.
NOTE:
Confirm that the compressor clutch is engaged (sound or visual
inspection) and intake door position is at FRESH when the DEF is
selected.
CHECKING INTAKE AIR
1. Press intake switch. Recirculation indicator should illuminate.
2. Press intake switch again. Fresh indicator should illuminate.
3. Listen for intake door position change (Slight change of blower sound can be heard.).
If NG, go to trouble diagnosis procedure for AT C - 6 9 , "
Intake Door Motor Circuit" .
If OK, continue the check.
NOTE:
Confirm that the compressor clutch is engaged (sound or visual inspection) and intake door position is at
FRESH when the DEF is selected.
CHECKING TEMPERATURE DECREASE
1. Press temperature control switch (DOWN, driver side) until 18°C is displayed.
2. Check for cold air at discharge air outlets.
If NG, go to trouble diagnosis procedure for AT C - 8 4 , "
Insufficient Cooling" .
If OK, continue the check.Conditions : Engine running at normal operating temperature
SJIA1002E
Page 433 of 3502

TROUBLE DIAGNOSIS
ATC-55
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AT C
CHECKING TEMPERATURE INCREASE
1. Press temperature control switch (UP, driver side) until 32°C is displayed.
2. Check for hot air at discharge air outlets.
If NG, go to trouble diagnosis procedure for AT C - 9 1 , "
Insufficient Heating" .
If OK, continue the check.
CHECKING A/C SWITCH
1. Press AUTO switch and A/C switch.
2. A/C switch indicator will turn ON.
Confirm that the compressor clutch engages (sound or visual inspection).
If NG, go to trouble diagnosis procedure for AT C - 7 8 , "
Magnet Clutch Circuit" .
If OK, continue the check.
CHECKING AUTO MODE
1. Press AUTO switch and A/C switch.
2. Display should indicate AUTO.
Confirm that the compressor clutch engages (sound or visual inspection). (Discharge air and blower
speed will depend on ambient, in-vehicle, and set temperatures.)
If NG, go to trouble diagnosis procedure for AT C - 5 6 , "
Power Supply and Ground Circuit for Auto Amp." , then
if necessary, trouble diagnosis procedure for AT C - 7 8 , "
Magnet Clutch Circuit" .
If all operational checks are OK (symptom cannot be duplicated), go to Incident Simulation Tests in GI-24,
"How to Perform Efficient Diagnosis for an Electrical Incident" and perform tests as outlined to simulate driv-
ing conditions environment. If symptom appears, refer to AT C - 3 5 , "
SYMPTOM TABLE" and perform applica-
ble trouble diagnosis procedures.
Page 435 of 3502

TROUBLE DIAGNOSIS
ATC-57
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COMPONENT DESCRIPTION
Unified Meter and A/C amp. (Automatic Amplifier)
The unified meter and A/C amp. has a built-in microcomputer which
processes information sent from various sensors needed for air con-
ditioner operation. The air mix door motor, mode door motor, intake
door motor, blower motor and compressor are then controlled.
When the various switches and temperature contorol switch are
operated, data is input to the unified meter and A/C amp. from the
display unit / display control unit using CAN communication.
Self-diagnosis functions are also built into unified meter and A/C
amp. to provide quick check of malfunctions in the auto air condi-
tioner system.
Potentio Temperature Control (PTC)
The PTC is built into the A/C and AV switch. It can be set at an inter-
val of 0.5°C in the 18°C to 32°C temperature range by turning tem-
perature control switch. The set temperature is displayed.
DIAGNOSIS PROCEDURE FOR A/C SYSTEM
SYMPTOM: A/C system does not come on.
RJIA2732E
RJIA3253E
SJIA0301E
Page 444 of 3502
ATC-66
TROUBLE DIAGNOSIS
Air Mix Door Motor CircuitBJS000G2
SYMPTOM
Discharge air temperature does not change.
Air mix door motor does not operate normally.
INSPECTION FLOW
*1ATC-47, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 2 to 6.*2ATC-96, "
Ambient Sensor Circuit"*3ATC-99, "In-vehicle Sensor Circuit"
*4ATC-102, "Sunload Sensor Circuit"*5ATC-66, "Air Mix Door Motor Circuit"*6ATC-47, "FUNCTION CONFIRMA-
TION PROCEDURE", see No. 13.
*7ATC-59, "
LAN System Circuit"*8ATC-124, "AIR MIX DOOR MOTOR"*9ATC-54, "Operational Check"
*10ATC-35, "SYMPTOM TABLE"*11ATC-105, "Intake Sensor Circuit"
RJIA3256E